Well it looks like all of the 10th Anniversary Diamond Edition SPFs have been identified --
click here to see the full list.
All, that is, except car #4 of 50 which is out there somewhere. If you know where it's at and what its chassis number is, please chime in. (UPDATE: Car #4 has since been identified as SP01921, and is painted Dark Silver.)
40 Dark Silver + 10 Amulet Red = 50 Diamond Editions
30 cars produced in 2004 + 20 cars produced in 2005 = 50 Diamond Editions